Light-emitting device and planar light source

Patent metadata

Field	Value
Publication number	US-2023085463-A1
Application number	US-202218047041-A
Country	US
Kind code	A1
Filing date	Oct 17, 2022
Priority date	Aug 31, 2020
Publication date	Mar 16, 2023
Grant date	—

Abstract

A light-emitting device includes a wiring board, a plurality of light-emitting elements disposed on the wiring board, a light-reflecting member covering a lateral surface of each of the plurality of light-emitting elements, a plurality of light-transmitting layers each located above an emission surface of a corresponding one of the plurality of light-emitting elements, a plurality of light-reflecting layers disposed on the plurality of light-transmitting layers, respectively, a light-diffusing layer disposed above the plurality of light-reflecting layers and the light-reflecting member, and a low-refractive-index layer located between the light-reflecting member and the light-diffusing layer, around each pair of one of the plurality of light-transmitting layers and one of the light-reflecting layers, and having a refractive index lower than that of the plurality of light-transmitting layers. Each of the plurality of light-reflecting layer has a width in a cross-sectional view thereof which is equal to or greater than that of a corresponding one of the plurality of light-transmitting layers.

First claim

What is claimed is:

1 . A method of producing a light-emitting device, comprising:
mounting a plurality of light-emitting elements onto a wiring board comprising an interconnect layer such that the light-emitting elements are electrically coupled to the interconnect layer; forming a light-reflecting member on the wiring board, the light-reflecting member covering at least a portion of lateral surfaces of each light-emitting element; disposing, onto respective upper surfaces of the light-emitting elements, multilayer structures each comprising a light-transmitting layer and a light-reflecting layer on the light-transmitting layer; providing a low-refractive-index layer; and disposing a light-diffusing layer over the low-refractive-index layer, the low-refractive-index layer having a refractive index lower than that of the light-transmitting layers.

2 . The method of claim 1 , wherein:
the step of providing the low-refractive-index layer comprises applying a light transmitting first resin material to an upper surface of the light-reflecting member and curing the first resin material.

3 . The method of claim 1 , wherein:
the step of providing the low-refractive-index layer comprises leaving the low-refractive-index layer as an air layer.

4 . The method of claim 1 , wherein:
the step of disposing multilayer structures comprises:
disposing the light-transmitting layer onto respective upper surfaces of the light-emitting elements; and
after disposing the light-transmitting layer,
providing the light-reflecting layer onto a corresponding one of the light-transmitting layers.

5 . The method of claim 4 , wherein:
in a cross-sectional view, each of the light-reflecting layers has a width which is equal to or greater than that of a corresponding one of the light-transmitting layers.

6 . The method of claim 1 , wherein:
the step of disposing multilayer structures comprises:
providing a sheet-shaped layered structure comprising a light-transmitting sheet and a light-reflecting sheet on the light-transmitting sheet;
cutting the sheet-shaped layered structure into a plurality of pieces; and
attaching each of the plurality of pieces of the sheet-shaped layered structure onto the upper surface of a corresponding one of the light-emitting elements.

7 . The method of claim 1 , wherein:
the light-reflecting member has one or more protrusions on an upper surface thereof.

8 . The method of claim 7 , wherein:
the one or more protrusions include a plurality of protrusions surrounding each light-emitting element in a plan view.

9 . The method of claim 1 , wherein:
the step of forming a light-reflecting member comprises:
providing a resin sheet having a plurality of through-holes provided at positions corresponding to the plurality of light-emitting elements on the wiring board; and
attaching the resin sheet onto the wiring board.

10 . The method of claim 9 , wherein:
the step of forming a light-reflecting member further comprises:
after attaching the resin sheet onto the wiring board, filling the through-holes with a second resin material.

11 . The method of claim 1 , wherein:
in a top plan view, each of the light-reflecting layers overlaps a corresponding one of the plurality of light-transmitting layers; and each light-transmitting layer encloses, within an outer periphery thereof, an emission surface of the corresponding light-emitting element in a top plan view.

12 . The method of claim 1 , wherein:
in a top plan view, each of the light-reflecting layers has a dotted pattern having a dot density that becomes higher toward a center of each of the light-reflecting layers from an outside thereof.

13 . The method of claim 1 , further comprising
providing the plurality of light-emitting elements and the wiring board comprising the interconnect layer before the step of mounting the plurality of light-emitting elements onto the wiring board.

14 . The method of claim 1 , wherein:
the interconnect layer comprises a first interconnect layer on the side of an upper surface of the wiring board and a second interconnect layer on the side of a lower surface of the wiring board, the first interconnect layer being electrically coupled to the plurality of light-emitting elements, the second interconnect layer being electrically coupled to a connector for coupling to an external control circuit.

Assignees

• Nichia Corp

Inventors

• Nakabayashi Takuya
• Yamashita Ryohei
• Emura Keiji
• Okahisa Tsuyoshi
• Katsumata Toshinobu

Classifications

• H10W90/00

  Package configurations · CPC title

• G02F1/133603 Primary

  with LEDs · CPC title

• G02F1/133606

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• G02F1/133605 Primary

  including specially adapted reflectors · CPC title

• G02F1/133612

  Electrical details · CPC title